1. Field of the Invention
This invention relates to a method and apparatus for editing and mounting visual information recorded on tape.
2. Description of the Prior Art
It is commonplace in many fields of technology to record information, such as electrocardiographic information, in a visual form on standardized elongated strips of tape. The amount of recorded data is often far in excess of that which is necessary or pertinent for immediate analysis and/or for storage and future reference. This problem is ordinarily solved by visually inspecting the tape for selection of representative segments which are removed with scissors for mounting on a mounting chart, thereby forming a composite record of the selected information.
Modern electrocardiographs are generally capable of producing 12 standardized leads proportional to potentials measured by electrodes placed at selected locations on the patient's body. These lead signals include:
Lead I - difference of potential between the left arm and the right arm PA1 Lead II - difference of potential between the left leg and the right arm PA1 Lead III - difference of potential between the left leg and the left arm PA1 Lead aVR - augmented difference in potential between the right arm and the left arm and leg electrically connected together PA1 Lead aVL - augmented difference in potential between the left arm and the right arm and left leg electrically connected together PA1 Lead aVF - augmented difference in potential between the left leg and the left and right arms electrically connected together PA1 Leads V.sub.1 through V.sub.6 - potential measurements, taken at predetermined chest locations of the patient.
An unedited ECG tape includes successive sections containing visually recorded information such as a line tracing for each of the above 12 leads. Numerous attempts have been made to provide an efficient editor for facilitating selection and removal of sample segments representative of each lead and for providing a standardized mounting chart for displaying and storing the selected segments. For example, U.S. Pat. No. 3,261,250 to Littmann discloses an ECG lead segment cutting device including a rectangular cutting blade adapted to remove segments of constant uniform size. Furthermore, U.S. Pat. No. 3,382,127 to Littmann et al discloses a method for mounting ECG lead segments of uniform size on a standardized chart including a frame adapted to facilitate alignment of the lead segments with preselected areas on the chart.
While the disclosed Littmann system is well suited for the purpose intended, an ideal ECG mounting system would permit all 12 lead segments recorded on standard 21/2 inch wide ECG tape to be displayed on one side of a standard chart (81/2 by 11 inches) with sufficient space left for patient data and comments. Obviously, the Littmann chart cannot provide these characteristics since the entire chart surface is used to display 12 leads. In the ideal system, each of the lead segments must be sufficiently long to display all of the required information. This length differs with the type of lead in question. For example, at least one lead, preferably lead II, should be long enough to permit identification of the auricular complex and accurately determine the pulse rate. Accordingly, lead II should be approximately 6 inches of standard ECG tape. The remaining leads may be considerably shorter. Accordingly, a simplified ECG tape editor system is needed for facilitating division of a standard ECG tape into selected segments of varying predetermined lengths, depending upon the type of information contained thereon. At the same time, the system should be adaptable to a variety of tape widths while facilitating accurate marking of desired tape segments for subsequent cutting into predetermined lengths required by the particular chart on which the segments are to be mounted.
Tape editing devices are, of course, notoriously well known for a variety of specific applications. For example, note U.S. Pat. No. 1,044,258 to Schaffer issued Nov. 12, 1912, which discloses a device for mending film including a film clamp, cutter and gauge mounted on a single base. No tape editor, however, has been disclosed which permits viewing of the tape for selection of desired segments and for marking of the ends of the selected segments in varying lengths depending upon the information contained on the segments.